The crew come across an abandoned ship with one survivor: Caroline Carmen, one of Lister's former crushes. She revives in the middle of the night and infects Lister with the dreaded Epideme virus, which threatens to kill him unless something is done. He tries talking with Epideme directly through a communication link, but nothing doing. He ends up losing an arm to the virus before Kochanski comes up with another solution.
- Starbug lands on an ice planet, Kryten suggests siphoning the water to refill the craft's supply, a scan reveals a starship buried beneath the glacier. The ship is the Leviathan, the engines are overloaded, it's believed the crew fled from something, a life reading is detected, the Leviathan crew lay dead throughout the ship, a body is found frozen in ice, Caroline Carmen, formerly of Red Dwarf and one of Lister's former girlfriends, she is bought on board Starbug.
The body won't defrost, in the middle of the night Caroline defrosts and shuffles into Lister's room while he sleeps and climbs into his bed, he mistakes her for Kochanski. Kryten knocks at the door and Lister hides Caroline under his duvet and bundles her into the shower, Kryten enters under the guise of late night cleaning, he's looking for Kochanski, he's still jealous Lister will prefer Kochasnki over him, Kochanski enters and Kryten's paranoia is shut down and he leaves, Lister tries to bed her, but he doesn't realize she wasn't the one who snuck in. She punches him and leaves, Lister goes to bed but he's forgotten his duvet, he opens the shower door and Caroline jumps him, he accidentally rips off one of her ears in the struggle, he sounds the alarm and makes for the door but Caroline grabs him and kisses him, he throws her off and she lays dead on the floor. Kryten rushes in with a scanner and finds the life signs have vanished, Lister faints.
Lister is examined, the life signs were from a dormant virus named Epideme, an intelligent germ created to block mental cravings of nicotine, but Epideme also blocked mentals signals for blood and oxygen, killing the patients, when Epideme runs out of hosts it freezes the body until a new one is available. Kryten suggests communicating with Epideme, the virus has the personality of an annoying game show host, Lister is unable to convince it to leave, so a new plan is enacted, Kochanski and Kryten suggests forcing the virus into Lister's arm and then amputate it. Lister agrees on the condition it's his left arm.
The surgery backfires and they have to amputate Lister's right arm. Worse yet, Epideme is only partially destroyed and his cells are regenerating. Lister heads onto the Leviathan with explosives wired to himself, he'll blow up himself and the virus, he leaves a will to the crew. During his last stand with Epideme, reveals the fate of the Leviathan crew, they weren't running from something, they were in a hurry to get to a planet that may have a cure on a research station.
Kryten also gets information from Epideme on how to increase Starbug's speed, the arrive at the planet, Delta 7, they find it was scorched to destroy an outbreak of Epideme. Epideme knew and fooled the others to buy time, Kochanski conjures up a new idea, she leaves the room and returns with a syringe, she has to stop Lister's heart, when she does she lets his corpse transfer Epideme to her left arm and amputates it, Cat faints in shock, Kochanski reveals her real arm tucked in her shirt, the amputated arm was Caroline's, injected with blood and adrenaline.
Kryten is astonished and as they leave they realize they forgot to resuscitate Lister, they do but he has only one arm now.